AFM to MAS Conversion

[Zoomy]

Hey;

I'm new to this board and so far it looks pretty good.
But in all the boards I'v gone to thru the years, I do not see much mentioned about a AFM to MAS conversion.

SplitSecond has a conversion kit for $800. Pretty pricey.

From the info I've gathered so far, I can do it for under $300.

I'm in the process of nailing down the details before I start buying parts.

I was wondering if anyone has attempted this Conversion..

[KC Ron Carter]

All on M30 but same issues.

This is my never do this, just say no, picture:





Here is my MAF from Split Second

The controller is in the glove box, and is indexed to allow me to play with settings and get back to smooth running.



Here is the Ford 65mm MAF and it is made in JAPAN.



If this engine was shiny enough to reflect,
you would see me smiling while taking the pictures.
Cause I really like the output of the MAF.

Six hours, DIY, including the indicator and can switch back to AFM in 2 minutes, Two screw clamps on MAF, two quick electrical connectors and the OE connector is tie rapped back out of the way.

I am getting a new dyno spring and the values can be verified then.

But the BUTT dyno is very impressed to say the least.
I am using the J C. chip also, a 3.71 ratio, with 265 Getrag.

The sweet spot of the m30 is now at 2200rpm where it was at 2800rpm.

That is the point where the rumble of the exhaust resonates in frequency with the intake. On the unmodified it is only seen on the cold mornings when the fuel system adds a little more fuel and the cold air is giving it's all.

I really like it.

[Zoomy]

Ron;

I'm glad to hear you like the conversion.
Really gives me a boost to keep going with this project.

I am working with a retired IBM Engineer, who says the conversion is theoretically pretty easy.

The BMW AFM voltage runs from about 3.5v at idle to 0v at WOT.

The Ford MAS voltage is about 1.5v at idle and goes up toward 9v at WOT.

For $20 my IBM friend is designing me a "voltage conditioner".
Which is basically a 4 way voltage divider with an op-amp to reverse to voltage direction.

I'm getting a used Ford MAS for $25 from the junk yard.

A Fuel Mix guage for $49 from Summit is the most expensive piece of the project.

A generic cone filter from Jegs for $46.

The only problem I'm having is finding the reduction coupler seen in your last pic. I may have to 'kludge' something from the junk yard.

When the project is finished, I'll give all the details so anyone willing to can give it a shot.

Later

[KC Ron Carter]

From Split Second the adapter is:

3-2.5" R 3" to 2.5" Black Reducer $28

3.5-3" R 3.5"to 3" Black Reducer $30

Check the price sheet:

http://www.splitsec.com/

[Zoomy]

That's the last place I'd expect to find parts.

Last time I looked at Split Second's site, they offered kits only.

Did you use SplitSecond's kit from the start or try it on your own, ie first pic.

Later.

[KC Ron Carter]

I am ashamed for the guy who did it.

I like my Split Second no reason to try any other.

Later,

[Zoomy]

Because of $$

I'm doing my own conversion.

That and faith in my IBM friend who is sure we can do it.

Gotta go, catch you on the board later.

[bimmerdream]

If you can do this conversion, I'll have your first born!!!! DO IT!!! e30 M3 people will kill for a cheap MAS!!! I know I would. and by the way, SplitSec MAF is Ford MAF as well. It's the one that comes on 3.0L V6 Rangers I believe.
Please, even if no one else is interested, keep ME informed on the progress!
Thank you!

[Jared at Pelican Parts]

How exactly did you tackle tying this into the ecu? Or is it a seperate control unit?

[bimmerdream]

Here's the idea:

MAF/MAS produces a signal
the singnal goes into a signal modifier box
the box "translates" the MAF/MAS signal into AFM signal (say, 5.7V of MAF/MAS = 2.6V of AFM) the modified signal goes into the ECU. It's sorta the same idea as a piggy-back fuel system.
The signal modifier box holds a chip with a translation algorithm in it, since I doubt the AFM output is linear. If I only knew electronic engineering, I would have done this set up ages ago!
(I'm sure the above description applies to the SS MAF kit as well)

[Jeff at WallWerks]

my curiosity is just how much hp will all of this
engineering get you?

[Zoomy]

Hey;

At first I didn't think any one was interested.
This is going to be a L-O-N-G project.

My wife & I have Quadruplets 4 1/2 yrs). So I only have a few hours a week to spend on this.

Mr Bimmerdream is partially right.

I will be using a MAS from a Ford.

The voltages are linear. And only an Op-Amp, a few resitors & capactors are needed for the voltage conversion.

It will be wired inline between the MAS & ECU.

Thanks to the Air-Fuel-Ratio Guage kit on this board, the only couple things I'll have to buy New is a Cone filter and a 3" to 2.5" coupler.

I'm going to start the Air-Fuel kit next week.
** By the way, Put the Capactor between then 2 IC's.
Or else the IC's will eventually die.

According to the Split Second web site, an E30 M3 had 178hp at the rear wheels at 152.2 on the torque.

Later

[bimmerdream]

You guys are so in the stone age with this AFM deal it's not funny!
The issue has been beaten to death first on DTMpower.net, and now on s14.net. The only people that seem to be interested in this deal are e30 M3 owners since loosing AFM would mean up to 20% increase in HP AT THE WHEELS for them due to physics of the s14 engine. Also, there was something called a "LINK" Box system invented by some guy Stan from Conneticut. No surprise there, Stan is an electronics engineer who happens to own an e30 M3. His method gets rid of AFM period, and instead relies on self-made Throttle Position Sensor signal to calculate volume of air entering the engine. After some tuning of fuel curves Stan achieved a whooping 35% increase in torque at the wheels, bringing the HP count to 200+ to the ground (He did have Gruppe A intake manifold though). I believe it's about 20+ horses over AFM>MAF method from Split Sec.
So, yes. there is a SIGNIFICANT improvement in horse power and torque, but more so in engine response to the driver.
To this point cost has been the problem with the system (MAF), and Stan's invention relies on a signal converter box that is not in production any more and is very hard to find.
SO, if my dear Internet friend can replicate ANYTHING that would get rid of the AFM and cost less than 200 bucks, he would be forever honored in the BMW enthusiasts hall of fame. I personally am keeping my fingers crossed for him. This can be a significant break through in old-style BMW performance.

Disclamer: I hate to proof read, so please, forgive me for my mistakes.

[bimmen325]

i like the idea,since i read the results grassroots motorsport magazine got with thier project e30 m3 ,they even posted thier dyno results on thier site ,i dont know if anyone on the board reads this mag but they usually have pretty good info ,thier results using the split second kit ,was 164.9 hp before and 176.8 hp after the kit was installed .torque went from 151.4 to 160.8. not bad at all even for the $800.00 ,i mean its alot but it unlike most mods really delivers . bmp also used this on thier e30 325 project . now if someone has a better and less expensive way ,that would be music to all e30 drivers.

[Zoomy]

I'm undertaking this project for 2 reasons.
1) My AFM needs replacing.
2) Cause I can.

Since I am building the electronics from scratch & other parts from 'junk yarks'. A lot of R&D/field enginereering, I should be able to build it for under $200.

I am working with a retired IBM guy who did this sort of stuff for a living.
He converted Kawasaki bikes in the 70's to electronic ingnition just for the fun of it.